The development of successful models for the initiation and characterization of in vitro transformed epithelial cells is needed since the majority of cancers are of epithelial cell origin. The choice of colon epithelium is based on a number of factors. Large bowel cancer currently represents the highest incidence of all visceral human neoplastic diseases in the United States. However, few in vitro studies have been done using colon or other gastrointestinal epithelia, since no good method to culture these cells was available. Our recent, exciting success in culturing human colon epithelium now allows us to pursue the much-needed in vitro transformation experiments which may help elucidate the mechanism(s) of oncogenesis. The specific aims of these studies are: (i) to transform human colon epithelial cells with chemical (azoxy-methane) and viral ("oncogene") carcinogens, (ii) to clone the transformants, then select and propagate stock cultures of several clones for characterization studies, and (iii) to compare characteristics displayed by in vitro transformed cells with normal cells and human colon cancer cells as a prelude to elucidating mechanisms of oncogenesis. Morphology, growth, cytogenetics, viral oncogene expression and cell surface and ionic changes will be assessed. These analyses should determine if specific features associated with colon cancer (e.g., induction of embryonic antigens such as CEA, changes in lectin binding, or expression of the 19-9 gylcolipid colon tumor antigen) occur upon cell transformation or are possibly a later event during cancer progression. The proposed research will also contribute to a better understanding of growth regulation and differentiation of human colon epithelial cells. Such information will provide a foundation for designing biologically relevant approaches to colon cancer diagnosis and therapy.